This invention relates to a flexible hose composed of a membrane which comprises soft and hard strip members alternately disposed in a spiral form. Self-support and shock-resistance are ensured and also excellent flexibility is obtained.
Within this technology it has heretofore been proposed to make a flexible hose of this type as shown in FIGS. 1 and 2. This hose has soft and hard synthetic resin strips 51 and 52 which are alternately disposed on the outer periphery of a tubular web 50 of fiber or the like to integrally join one to the other, as seen in FIG. 1.
This conventional hose renders the tubular web 50 susceptible to the influence of fluid substances therein. The web is easily worn out or torn. This will greatly imperil functionality because of extension of the soft synthetic resin 51 by the tubular web 50 in the axial direction of the hose. As a result, the soft synthetic resin 51 is subjected to elastic and extensional deformation to a great extent when tensile force is applied to the hose. This dynamic characteristic shortens the hose life by repetition of such elastic deformation.
In order to eliminate this disadvantage, Japanese patent examined publication No. 8965/74, and Japanese utility model examined publication No. 30787/81, provide, for instance, a series of splicing yarn members along the axial direction of the hose in the center of the thicknesses of the soft and hard synthetic resins 51, 52 as shown herein in FIG. 2. This technique enables the hose to prevent the splicing yarn members from being worn away by fluid substances in the hose. They involve, however, a further difficulty in decreasing the strength since bonding forces are non-uniform by insertion of the splicing yarn members 53 between synthetic resin portions 51a, 51b and 52a, 52b as helically wound and diametrically divided from the soft and hard synthetic resins 51, 52.